What is the probability (A1 A2 A3 | A1) ?

What is the probability (A1 | A1 U A2 U A3) ?

What is the probability (A3(complement) | A1 A2)?

I have been working on these problems for over an hour. I made a venn diagram, but it is wacky. I am also confused how to treat situations such as P ((A1 A2 A3) A1) like in the first problem.